'\" te
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.TH DF_UFS 8 "Feb 25, 2005"
.SH NAME
df_ufs \- report free disk space on ufs file systems
.SH SYNOPSIS
.LP
.nf
\fBdf\fR \fB-F\fR ufs [\fIgeneric_options\fR] [\fB-o\fR i] [\fIdirectory\fR | \fIspecial\fR]
.fi

.SH DESCRIPTION
.sp
.LP
\fBdf\fR displays the amount of disk space occupied by \fBufs\fR file systems,
the amount of used and available space, and how much of the file system's total
capacity has been used.The amount of space reported as used and available is
less than the amount of space in the file system; this is because the system
reserves a fraction of the space in the file system to allow its file system
allocation routines to work well. The amount reserved is typically about 10%;
this can be adjusted using \fBtunefs\fR(8). When all the space on the file
system except for this reserve is in use, only the superuser can allocate new
files and data blocks to existing files. When the file system is overallocated
in this way, \fBdf\fR might report that the file system is more than 100%
utilized.If neither \fIdirectory\fR nor \fIspecial\fR is specified, \fBdf\fR
displays information for all mounted ufs file systems.
.SH OPTIONS
.sp
.LP
The following options are supported:
.sp
.ne 2
.na
\fB\fIgeneric_options\fR\fR
.ad
.RS 19n
Options supported by the generic \fBdf\fR command. See \fBdf\fR(8) for a
description of these options.
.RE

.sp
.ne 2
.na
\fB\fB-o\fR\fR
.ad
.RS 19n
Specify \fBufs\fR file system specific options. The available option is:
.sp
.ne 2
.na
\fB\fBi\fR\fR
.ad
.RS 5n
Report the number of used and free inodes. This option can not be used with
\fIgeneric_options\fR.
.RE

.RE

.SH FILES
.sp
.ne 2
.na
\fB\fB/etc/mnttab\fR\fR
.ad
.RS 15n
list of file systems currently mounted
.RE

.SH SEE ALSO
.sp
.LP
\fBdf\fR(8), \fBfsck\fR(8), \fBfstyp\fR(8), \fBtunefs\fR(8),
\fBmnttab\fR(5), \fBattributes\fR(7), \fBufs\fR(4FS),
.SH NOTES
.sp
.LP
\fBdf\fR calculates its results differently for mounted and unmounted file
systems. For unmounted systems, the numbers reflect the 10% reservation. This
reservation is not reflected in \fBdf\fR output for mounted file systems. For
this reason, the available space reported by the generic command can differ
from the available space reported by this module.
.sp
.LP
\fBdf\fR might report remaining capacity even though \fBsyslog\fR warns
\fBfilesystem full\fR. This issue can occur because \fBdf\fR only uses the
available fragment count to calculate available space, but the file system
requires contiguous sets of fragments for most allocations.
.sp
.LP
If you suspect that you have exhausted contiguous fragments on your file
system, you can use the \fBfstyp\fR(8) utility with the \fB-v\fR option. In
the \fBfstyp\fR output, look at the \fBnbfree\fR (number of blocks free) and
\fBnffree\fR (number of fragments free) fields. On unmounted filesystems, you
can use \fBfsck\fR(8) and observe the last line of output, which reports,
among other items, the number of fragments and the degree of fragmentation. See
\fBfsck\fR(8).
